Abstract: Multiple suppression is the key to marine seismic data processing.Efficient and accurate identification and suppression of multiples while protecting primary reflected waves is the focus of seismic data processing.This study carried out the multiple suppression in the S-transform domain using the CMP stacking based on the similarity of seismic signals between the common midpoint (CMP) gather and the stack trace.First,the initial multiple subtraction was completed through the normal moveout (NMO) correction of multiple velocity and subtracting the stack trace data from the CMP gather data.As a result,the residual multiples in the wave field exist in the form of random noise.Then,the NMO correction was conducted for the velocity of primary reflected waves of the seismic wave field, for which multiples were subtracted.Afterward,the similarity filtering was conducted for the S-transform spectra of the CMP gather,with the stack trace of the primary reflected wave velocity as the initial model.In this way,the residual multiples were eliminated.The validity tests based on both the theoretical data and the actual data show that the method proposed in this study can efficiently suppress multiples and improve the imaging precision of reflected waves.